Apparatus for mounting and bonding a rocket grain within a case



June 28, 1960 H. 1 EDWARDS 2,942,645

' APPARATUS FOR MOUNTING AND BONDING A ROCKET GRAIN WITHIN A CASE Filed Feb. 11, 1957 4 Sheets-Sheet 1 INVENTOR. H. L. EDWARDS F/G. 4 $1 7 AiZZNEJ S June 28, 1960 H. L. EDWARDS 2,942,645

APPARATUS FOR MOUNTING AND BONDING A ROCKET GRAIN WITHIN A CASE Filed Feb. 11, 1957 4 Sheets-Sheet 2 FIG. 2.

INVENTOR. H. L. E 0 WARDS MHIZ$M 7'7 NEVS June 28, 1960 H. 1.. EDWARDS APPARATUS FOR MOUNTING AND BONDING A ROCKET GRAIN WITHIN A CASE Filed Feb. 11, 1957 4 Sheets-Sheet //////1 a I I l I I I l I I I I l I 1 I I I I I I 11 \II vllaV NIO LEE

INVENTOR h. L. EDWARDS TOR/VEYS Filed Feb. 11, 1957 June-28, 1960 H. 1.. EDWARDS 2,942,645

APPARATUS FOR MOUNTING AND BONDING A ROCKET GRAIN WITHIN A CASE 4 Sheets-Sheet 4 32 'INYENTOR. i A h. 1.. EDWARDS T0 NEVS al-ml United States Patent APPARATUS FOR MOUNTING AND BONDING A ROCKET GRAIN WITHIN A CASE Harold L. Edwards, Bartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware Filed Feb. 11, 1957, Ser. No. 639,255

7 Claims. (Cl. 154-1) This invention relates to apparatus for resiliently mounting an inner rigid member within an outer rigid member.

This invention is particularly adapted to a method of mounting a rocket grain within a case although the apparatus is suitable for preparing other structures wherein the same problems are present. Rocket grains comprising a solid oxidant as a binder, such as asphalt or rubber, are widely used in order to provide thrust for aircraft. Even though a flexible binder is used, the resulting grain is somewhat fragile and the problem exists in that such grains are subject to breakage. If a grain fractures, the burning characteristics of the unit are changed and there is even a possibility of explosion. One attempt to solve this problem has been to provide a flexible mounting at at least one end of the grain so that the grain is resiliently mounted in the case. In some instances, this has not been satisfactory because some units so mounted have failed to pass a dropping test comprising dropping the unit from a four foot height, a widely used test.

A new approach comprises the addition of strips of resilient material positioned between the grain and the case. Rubber, particularly sponge rubber, and cork have been used for mounting the grain in the case and this appears to be satisfactory in preventing breakage. In order to provide good stability, such resilient strips are bonded to the grain and to the case in order to maintain the grain in position. This invention relates to apparatus for assembling the grain and the case and for applying a bonding material to the resilient strips after the grain is inserted in the case.

The following are objects of this invention.

An object of this invention is to provide apparatus for resiliently mounting a substantially rigid inner member within an outer substantially rigid member. A further object of this invention is to provide apparatus for supplying adhesive material to a resilient member positioned between a rocket grain and a case.

Other objects and advantages of this invention will be apparent to one skilled in the art upon reading the accompanying disclosure, including the accompanying drawing which comprises:

Figure 1, a vertical elevation of the assembling apparatus showing the rocket grain being lowered into position;

Figure 2, a similarview showing the rocket grain in position and the case being lowered over it, the case being shown in cross section;

Figure 3, a view similar to the Figure 2 showing the rocket case in position;

Figure 4, a vertical cross section of the completed rocket;

Figure 5, an isometric view of the end portion of one of the compression fingers; and

Figure 6, a horizontal cross section of one of the resilient strips in position between the rocket grain and case before the compression fingers have been removed as shown on line 6-6 of Figure 3.

Referring to Figure 1, the apparatus comprises a base 10, compression fingers 11 and center support 12. Each finger 11 is attached to base 10 by a pin 13 in a slot 14 of car 15. Each finger 11 is similarly attached to center support 12 by a pin 16 in the slot 17 of ear 18. A spring 19 separates center support 12 from the upper portion of base 10. Each finger 11 is provided with a relatively flat conduit 20 (Figure 5) which is connected to a flexible conduit 21 and to a pump 22 (Figure 3).

The rocket grain 23 has attached to its outer surface resilient strips 24. A plurality of supporting legs 25 are attached to the bottom of the grain. An adapter plate 26 is provided to rest upon the upper portion of center support 12 and to support rocket grain 23. This plate is provided with bottom depression 26;: adapted to fit on center support 12 and top depression 25b adapted to engage supporting legs 25.

In the operation, when it is desired to assemble a complete rocket, the grain 23 to which are attached resiiient strips 24 and legs 25, is lowered onto adapter 26 which rests on center support 12. Compression fingers 11 are spaced sufficiently far apart so as not to interfere with these strips 24 as the grain is lowered into position. rests on center support 12, this support is forced downward against the force of spring 19 thus causing ears 18 to exert a force on pins 16 towards the center line of the apparatus. In this way, fingers 11 are forced inward thus compressing strips 24.

With the grain in this position, illustrated in Figure 2, the rocket case 30 is lowered in position supported by a lifting frame 31 which is provided with slidable support pins 32. When the case 30 has been lowered completely over the grain 23, as illustrated in Figure 3, the pins 32 are moved inward in supporting relation with adapter 26. When lifting frame 31 is raised upward the entire assembly of case 30, grain 23, strips 24, and adapter 26 is lifted from the assembling apparatus. As the rocket assembly is raised, pump 22 is actuated to force bonding material through the flexible conduits 21 and the rigid conduits 20 and discharges it along the outer edge'of strips 24. The rocket assembly is completed by inverting case 30, removing adapter 26, and installing end piece 32 (Figure 4).

Figure 5 is a view of the end portion of one of the fingers 11 showing conduit 20 in greater detail. Figure 6 is a cross section on line 6-6 of Figure 3. It shows a finger 11 in place between grain 23 and case 30. Adhesive layer 33, previously applied holds strip 24 in position on-the grain. Adhesive 35 is shown in conduit 20 which is forced between strips 24 and case 30 as the fingers 11 are removed.

The presence of rubber strips 24 has a very slight effect upon the firing characteristics of a JATO unit so bonded. In one series of runs, 4 strips, one-inch by inch by 10 inches of sponge rubber were applied to the forward end of a grain, the strips being placed degrees apart. The strips were bonded with Dutch Brand 711 Rubber Cement, Rubber Bonding Cement and Thiokol Bonding Agent. The first two of these products are made by Van Clees Bros., Inc. of Chicago, and the third by the Thiokol Corp. Strips so bonded required a pull of 1000 pounds or more to break the bonds and no signs of failure were observed when the units were dropped four feet.

As many possible embodiments can be made of this invention without departing from the scope thereof, it is to be understood that all matter herein set forth is However, when the weight of grain 23 a to -be'interpreted as illustrative and not as unduly limiting the invention.

I claim;

member by means 'of resilient material bonded between said members comprising, a support base; a center support'resiliently mounted on said support base; a plurality of fingers movably attached to said supPOrt base and said center support, .said'fingers being adapted to V compress said resilient material; a bonding material supply' conduit extending longitudinally of each said finger;

means. to supply bonding material to the bonding material supply conduit in each said finger; said elements being mechanically associated so that said plurality of 'ears on said center support,'each slotted ear on said center support being aligned with a'corresponding ear on said support base, a finger adjustably mounted on each pair of aligned earsby means comprising two pins on each finger, one pin being adapted to ride in the slot in the ear on said support base and a second pin being adapted to ride in the slot'in'the' car on said center support,.said fingers moving to compress material therebetween when said center support moves downwardly; a bonding material supply conduit extending longitudinally of each said finger; means to supply bondingmaterial to the bonding material supply conduit in each" said finger; an adapter plate movably mounted on said center support, said adapter plate' being-adaptedto support fingers move inwardlywhen said center support moves downwardly.

to'compress said resilient material; a bonding material supply conduit extending longitudinally of each said fin er; means to supply bonding material to the bonding material supply conduit in each said finger; said elements being mechanically associated'so that said plurality of fingers move inwardly when said center support moves downwardly.

3. Apparatus for resiliently mounting a substantially V rigid inner member within a substantiflly rigid outer member by means of resilient material bondedbetween said members comprising, a support base; a center support resiliently mounted'on said support base; a plurality of fingers movably attached'to said support: base a and said center support; a'bonding material supply conduit extending longitudinally of each said finger; means to supply bonding material to the bonding material sup- 9 ply conduit in each said finger; an adapter. plate adapted to fit and rest on said center support, said adapter plate being adapted to support said inner'member; said elements being mechanically associated so that said plurality of fingers move inwardly when said center support moves 'downwardlyra lifting'frame; and a plurality of v i slidable support'pins' mounted in thealower, end portion lof said lifting frame, said pins being movable toia first a position to support saidouter member alone and to a 1 second position t'ofsup'port said inner and outer members as a unit.

'4'. Apparatus for resiliently mounting a rocket grain within a case by means of resilient material bonded besaid inner member; a lifting frame; a plurality of slidable support pinsmounted in the lower end portion of said lifting'frame, said pins being movable to. the first position to support said outer member, alone and toe second position "tosupport said inner'and outer member as a unit; and means tonio've' said lifting frame. 6. Apparatus for resilientlymounting a substantially 'rigid inner member within a substantially rigid outer member by means of resilientmaterial bonded between said members comprising a support base; a center support resiliently mounted on said supportbase; a plurality of fingers movably attached to said support base 'and'said center support; an adapter plate adapted to fit and rest on said center support, said adapter: plate being adapted to support said inner member, a' bonding material supply conduit extending longitudinally 'of each said finger; and means to supply bonding material to the bonding material supply conduit'jin each" said finger; said elements being mechanically associatedso that said plurality of fingers move inwardly when said center support her; a plurality of slotted ears on said support base; a

tween said grain 'and'case comprising a support base; a

means to supply bonding material to thebonding Ina-' terial supply conduit in each said finger; an adapter plate adapted to fit and rest on said center support, said adapter 7 plate being adapted to support said grain; said elements lacing; mechanicallytassociated so that saidrplurality of fingers moveinwardly when said center support moves downwardly; a liftingqframe; and plurality of slidable support pins mounted in the lower end portion of said liftingframe, said pins being movable to a first position "to support said case alone and to a second position to t supportsaid grain and case as a unit;

' 5. Apparatus for'resiliently mounting a substantially rigidinner'member within a substantially rigid outer member by means of resilientmaterialbonded between port resiliently mounted on said support base; a plurality of slotted ears on said support base; a plurality of slotted said members comprising, a support base; a center supplurality of slottedears on said center support, each slotted ear. on said center rsupport being aligned with a corresponding car on said support base; a finger adjust- Tably mounted onieach'pair of aligned cars by means comprising two pins on each finger, one pin being adapted to ride in the slot in the car on said support'base and the second pin being adapted to'ride in the norm the car on said center support; a bonding material supply conduit extending longitudinally of each saidfinger; and means to supply'bonding material to the bonding material supply conduit in'each said finger; said elements being mechanically 'associated so that said plurality of v fingers move inwardly when saidrcenterrsupport moves downwardly. e I v V References Cited in the fileof this patent NirED STATES PATENTS V 7 1,949,772 Allen Mar. 6, 1934 1,999,417 Loweletxal. Apr. 30,1935 2,334,558 Jones Nov. 16, 1943 2,434,942 Magee r Jan. 27, 1948 2,482,133 Sweetser Sept. 20, 1949 2,636,472. Vargo et a1. Apr. 28, 1953 2,755,840 Bartley July 24, 1956 2,785,458 V V 1957 2,800,871 1957 2,825,477 7 I 1958 a FOREIGN iATENTS 26,430 a Great Britain 1907 by am 

